Faced with the depletion of fossil energy resources and given the current context of the fight against climate change, Renewable Energies (RE) represent an increasingly growing challenge. Of all these energies, those ...Faced with the depletion of fossil energy resources and given the current context of the fight against climate change, Renewable Energies (RE) represent an increasingly growing challenge. Of all these energies, those resulting from the biomethanization of biomass now provide an opportunity in the world of farmers and breeders. The treatment of agro-pastoral residues by anaerobic digestion has been the subject of renewed interest in recent years, thanks in particular to the production of energy from biomass, not to mention the production of fertilizers from effluents. Expelled from the digesters. This method of transformation offers many environmental, socio-economic and agricultural interests. Indeed, the biogas obtained from organic matter allows, among other things, to cook, light houses, and produce electricity and heat. The objective of this study is to compare the construction techniques and costs of the biodigester models that exist in Senegal. There are many biodigesters, the choice of an installation depends on the available space and the nature of the soil. Several types of biodigester technologies are installed in Senegal. The GGC 2047 fixed dome, the RMB geomembrane and the BEG geomembrane. First we will describe the construction techniques of the modified GGC model fixed dome biodigester, then of the RMB model geomembrane and finally of the BEG model geomembrane.展开更多
The indispensable role of energy in the correct functioning of economies and the current depletion of fossil fuels which are not renewable, have made the search for alternative energy sources a major point of reflecti...The indispensable role of energy in the correct functioning of economies and the current depletion of fossil fuels which are not renewable, have made the search for alternative energy sources a major point of reflection worldwide. Vegetable oils are increasingly being considered as a possible replacement for fossil fuels in countries of the south and North. In order to vulgarize the use of vegetable oil as fuel, it is essential that analytical protocols and standards are elaborated to assure the quality of oils as fuels. This work aims at developing protocols for the characterization of oilseeds and their resultant oils in a bid to ensure their quality for direct use as Biofuels or better still to serve as raw material in producing Biofuels. These protocols have the advantage of being reproducible, fast, and simple to implement compared to those used in Europe to characterize the oils (very complex and expensive, applied to petroleum products). Cotton, Jatropha curcas, white sesame, and peanut grains were acquired from the Zogona local market, Ouagadougou, and oil extraction was done at the village level. The resultant oils were characterized. Their physicochemical parameters (water content, oil content, acid index, the calorific value, density, and viscosity....) were evaluated at the Biomass Energy and Biofuels Laboratory (LBEB) of the International Institute for Water and Environmental Engineering (2iE) and the Burkinabé National Hydrocarbons Authority (SONABHY) Laboratory. The oilseed grain cakes (moisture, ash rate, rate of volatile matter, and oil content...) were also analysed.展开更多
The results of this study show that the Nusselt number decreases with the increase of the dimensionless thermal conductivity and the Prandtl, Froude numbers. The increased Reynolds, Jacob numbers and the dimensionless...The results of this study show that the Nusselt number decreases with the increase of the dimensionless thermal conductivity and the Prandtl, Froude numbers. The increased Reynolds, Jacob numbers and the dimensionless thickness of porous layer leads to an increase the Nusselt number.展开更多
The study of forced convection in a porous medium has aroused and still arouses today the interest of many scientists and industrialists. A considerable amount of work has been undertaken following the discovery of th...The study of forced convection in a porous medium has aroused and still arouses today the interest of many scientists and industrialists. A considerable amount of work has been undertaken following the discovery of the phenomenon. Solving a standard problem of forced convection in porous media comes down to predicting the temperature and velocity fields as well as the intensity of the flow as a function of the various parameters of the problem. A numerical study of the condensation in forced convection of a pure and saturated vapor on a vertical wall covered with a porous material is presented. The transfers in the porous medium and the liquid film are described respectively by the Darcy-Brinkman model and the classical boundary layer equations. The dimensionless equations are solved by an implicit finite difference method and the iterative Gauss-Seidel method. Our study makes it possible to examine and highlight the role of parameters such as: the Froude number and the thickness of the porous layer on the speed and the temperature in the porous medium. Given the objective of our study, the presentation of velocity and temperature profiles is limited in the porous medium. The results show that the Froude number does not influence the thermal field. The temperature increases with an increase in the thickness of the dimensionless porous layer. The decrease in the Froude number leads to an increase in the hydrodynamic field.展开更多
文摘Faced with the depletion of fossil energy resources and given the current context of the fight against climate change, Renewable Energies (RE) represent an increasingly growing challenge. Of all these energies, those resulting from the biomethanization of biomass now provide an opportunity in the world of farmers and breeders. The treatment of agro-pastoral residues by anaerobic digestion has been the subject of renewed interest in recent years, thanks in particular to the production of energy from biomass, not to mention the production of fertilizers from effluents. Expelled from the digesters. This method of transformation offers many environmental, socio-economic and agricultural interests. Indeed, the biogas obtained from organic matter allows, among other things, to cook, light houses, and produce electricity and heat. The objective of this study is to compare the construction techniques and costs of the biodigester models that exist in Senegal. There are many biodigesters, the choice of an installation depends on the available space and the nature of the soil. Several types of biodigester technologies are installed in Senegal. The GGC 2047 fixed dome, the RMB geomembrane and the BEG geomembrane. First we will describe the construction techniques of the modified GGC model fixed dome biodigester, then of the RMB model geomembrane and finally of the BEG model geomembrane.
文摘The indispensable role of energy in the correct functioning of economies and the current depletion of fossil fuels which are not renewable, have made the search for alternative energy sources a major point of reflection worldwide. Vegetable oils are increasingly being considered as a possible replacement for fossil fuels in countries of the south and North. In order to vulgarize the use of vegetable oil as fuel, it is essential that analytical protocols and standards are elaborated to assure the quality of oils as fuels. This work aims at developing protocols for the characterization of oilseeds and their resultant oils in a bid to ensure their quality for direct use as Biofuels or better still to serve as raw material in producing Biofuels. These protocols have the advantage of being reproducible, fast, and simple to implement compared to those used in Europe to characterize the oils (very complex and expensive, applied to petroleum products). Cotton, Jatropha curcas, white sesame, and peanut grains were acquired from the Zogona local market, Ouagadougou, and oil extraction was done at the village level. The resultant oils were characterized. Their physicochemical parameters (water content, oil content, acid index, the calorific value, density, and viscosity....) were evaluated at the Biomass Energy and Biofuels Laboratory (LBEB) of the International Institute for Water and Environmental Engineering (2iE) and the Burkinabé National Hydrocarbons Authority (SONABHY) Laboratory. The oilseed grain cakes (moisture, ash rate, rate of volatile matter, and oil content...) were also analysed.
文摘The results of this study show that the Nusselt number decreases with the increase of the dimensionless thermal conductivity and the Prandtl, Froude numbers. The increased Reynolds, Jacob numbers and the dimensionless thickness of porous layer leads to an increase the Nusselt number.
文摘The study of forced convection in a porous medium has aroused and still arouses today the interest of many scientists and industrialists. A considerable amount of work has been undertaken following the discovery of the phenomenon. Solving a standard problem of forced convection in porous media comes down to predicting the temperature and velocity fields as well as the intensity of the flow as a function of the various parameters of the problem. A numerical study of the condensation in forced convection of a pure and saturated vapor on a vertical wall covered with a porous material is presented. The transfers in the porous medium and the liquid film are described respectively by the Darcy-Brinkman model and the classical boundary layer equations. The dimensionless equations are solved by an implicit finite difference method and the iterative Gauss-Seidel method. Our study makes it possible to examine and highlight the role of parameters such as: the Froude number and the thickness of the porous layer on the speed and the temperature in the porous medium. Given the objective of our study, the presentation of velocity and temperature profiles is limited in the porous medium. The results show that the Froude number does not influence the thermal field. The temperature increases with an increase in the thickness of the dimensionless porous layer. The decrease in the Froude number leads to an increase in the hydrodynamic field.
